Alistra tuna is a species of Hahniidae spider endemic to New Zealand.
This species was described as Tawerana reinga in 1970 by Ray Forster from a female specimen. In 1986 it was transferred to the Alistra genus. The holotype is stored in Otago Museum.
The female is recorded at 2.03mm in length. The legs are coloured yellow brown. The abdomen has a pale marking dorsally.
This species is only known from Taumaranui, New Zealand.
Under the New Zealand Threat Classification System, this species is listed as "Data Deficient" with the qualifiers of "Data Poor: Size", "Data Poor: Trend" and "One Location".